// CRFClassifier -- a probabilistic (CRF) sequence model, mainly used for NER.
// Copyright (c) 2002-2008 The Board of Trustees of
// The Leland Stanford Junior University. All Rights Reserved.
//
// This program is free software; you can redistribute it and/or
// modify it under the terms of the GNU General Public License
// as published by the Free Software Foundation; either version 2
// of the License, or (at your option) any later version.
//
// This program is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
// GNU General Public License for more details.
//
// You should have received a copy of the GNU General Public License
// along with this program; if not, write to the Free Software
// Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
//
// For more information, bug reports, fixes, contact:
//    Christopher Manning
//    Dept of Computer Science, Gates 1A
//    Stanford CA 94305-9010
//    USA
//    Support/Questions: java-nlp-user@lists.stanford.edu
//    Licensing: java-nlp-support@lists.stanford.edu

package edu.stanford.nlp.ie.crf; 
import edu.stanford.nlp.util.logging.Redwood;

import edu.stanford.nlp.math.ArrayMath;
import edu.stanford.nlp.optimization.*;
import edu.stanford.nlp.sequences.*;
import edu.stanford.nlp.util.*;

import java.io.*;
import java.util.*;
import java.util.zip.GZIPInputStream;

/**
 * Subclass of CRFClassifier that performs dropout feature-noisying training
 *
 * @author Mengqiu Wang
 */
public class CRFClassifierFloat<IN extends CoreMap> extends CRFClassifier<IN>  {

  /** A logger for this class */
  private static Redwood.RedwoodChannels log = Redwood.channels(CRFClassifierFloat.class);

  protected CRFClassifierFloat() {
    super(new SeqClassifierFlags());
  }

  public CRFClassifierFloat(Properties props) {
    super(props);
  }

  public CRFClassifierFloat(SeqClassifierFlags flags) {
    super(flags);
  }

  @Override
  protected double[] trainWeights(int[][][][] data, int[][] labels, Evaluator[] evaluators, int pruneFeatureItr, double[][][][] featureVals) {
    CRFLogConditionalObjectiveFloatFunction func = new CRFLogConditionalObjectiveFloatFunction(data, labels,
        featureIndex, windowSize, classIndex, labelIndices, map, flags.backgroundSymbol, flags.sigma);
    cliquePotentialFunctionHelper = func;

    QNMinimizer minimizer;
    if (flags.interimOutputFreq != 0) {
      FloatFunction monitor = new ResultStoringFloatMonitor(flags.interimOutputFreq, flags.serializeTo);
      minimizer = new QNMinimizer(monitor);
    } else {
      minimizer = new QNMinimizer();
    }

    if (pruneFeatureItr == 0) {
      minimizer.setM(flags.QNsize);
    } else {
      minimizer.setM(flags.QNsize2);
    }

    float[] initialWeights;
    if (flags.initialWeights == null) {
      initialWeights = func.initial();
    } else {
      try {
        log.info("Reading initial weights from file " + flags.initialWeights);
        DataInputStream dis = new DataInputStream(new BufferedInputStream(new GZIPInputStream(new FileInputStream(
            flags.initialWeights))));
        initialWeights = ConvertByteArray.readFloatArr(dis);
      } catch (IOException e) {
        throw new RuntimeException("Could not read from float initial weight file " + flags.initialWeights);
      }
    }
    log.info("numWeights: " + initialWeights.length);
    float[] weights = minimizer.minimize(func, (float) flags.tolerance, initialWeights);
    return ArrayMath.floatArrayToDoubleArray(weights);
  }
} // end class CRFClassifierFloat